Figure 1.

A 27-year-old patient with a cT4N2 undifferentiated carcinoma of the nasopharynx who received 3 cycles of Cisplatin and Gemcitabine induction chemotherapy before concurrent chemoradiotherapy. The planning contrast-enhanced computed tomography (CT) (A) demonstrates excellent response to the induction treatment but fails to detect residual perineural involvement of the left facial nerve, visualized as an asymmetrical enhancement on the planning T1-weighted contrast-enhanced magnetic resonance imaging (MRI) (B)—white arrow. The facial nerve involvement could be tracked down to the left parotid and was consequently included in the radiation treatment volume.